This invention relates to cogeneration systems and more particularly to microprocessor-based control sub-systems for packaged cogeneration systems.
In recent years, the use of cogeneration systems has become increasingly popular as a vehicle for reducing costs associated with energy usage in commercial and industrial operations. In a typical cogeneration system, an electrical power generator, such as a gas-fired turbine driving a generator, is used to generate electricity for supplying the electrical needs of the installation. Any excess electrical power generated is sold to the power company, and electrical power is purchased from the power company only to the extent necessary to supplement the amount of electrical power produced by the cogeneration system. Wastes such as heat loss are eliminated by utilizing heat generated as a result of production of electrical power for supplying or at least contributing to, heat and/or cooling demands for the installation. Heat produced as a result of operation of the gas-fired turbine is extracted by way of a heat exchanger and used in supplying heating and cooling demands for the installation.
In view of the increasing popularity of the cogeneration philosophy various manufacturers are producing packaged cogeneration systems including gas-fired turbine engine-generator, for example, with an associated digital computer for controlling the operation of a cogeneration system including monitoring and control of the engine governor, engine fail-safe controls, control of electrical production, switch gear, pumps, valves, etc. of the cogeneration system.
Packaged cogeneration systems with low-functionality controllers make the economics of cogeneration less attractive, and this decreases the marketability of small (kilowatt) cogeneration systems. Cogeneration controllers that can implement integrated and advanced control and that possess information, diagnostics, and communication features are not presently available commercially. Presently, costly customer-designed control sub-systems are necessary to provide such features.
Thus it would be desirable to have a family of advanced controllers that addresses the technical and cost control requirement for packaged, gas-fired cogeneration systems. In particular, it would be desirable to have a family of controllers which possess standardized functions to address modularity of both control hardware and software and cost effectively address the spectrum of packaged cogeneration market needs.
It would also be desirable to have a control sub-system for operating a cogeneration system reliably at maximum economic performance while meeting the cogeneration system operating constraints.